Multi-mode Heater for Diesel Emission Fluid Tank
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Solution Overview
Problem
Aqueous Urea Solutions used in diesel exhaust treatment systems are prone to freezing at temperatures around −11° C, necessitating effective heating methods to prevent fluid degradation and system damage.
Innovation Solution
A dual-mode heater assembly comprising a high-power heater adjacent to the tank and a lower-power heater, powered by external and vehicle sources respectively, with a control module and temperature sensors to regulate temperature and prevent overheating, utilizing thermal insulation to enhance heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single high-power heater is used to prevent freezing of Aqueous Urea Solution, then the heating effectiveness is improved, but the energy consumption and risk of overheating increase
Solution Approach 1:
The heating system is segmented into two distinct heaters: a high-power heater (first heater) for rapid thawing and a low-power heater (second heater) for maintenance heating. This segmentation allows the system to use appropriate heating power based on actual temperature needs, preventing both freezing and overheating while optimizing energy consumption.
Solution Approach 2:
The system changes the heating parameter (power level) based on temperature conditions. The control module switches between high-power and low-power heating modes, or combines both heaters, depending on the measured temperature of the Aqueous Urea Solution. This dynamic parameter adjustment ensures effective freezing prevention without excessive energy consumption or overheating risk.
2Speed
If a high-power heater is used to rapidly thaw frozen fluid, then the thawing speed is improved, but the risk of fluid degradation and system damage increases
Solution Approach 1:
The heating system is divided into two stages with different power levels. The first heater provides high-power rapid thawing when the fluid is frozen, while the second heater provides gentle maintenance heating once the fluid reaches operational temperature. This segmentation enables fast thawing without prolonged exposure to high temperatures that could cause fluid degradation.
Solution Approach 2:
The control module continuously monitors the temperature of the Aqueous Urea Solution and adjusts heater operation accordingly. When the fluid reaches a safe temperature range, the control module reduces or shuts off the high-power heater, preventing overheating and fluid degradation while maintaining the fluid above freezing point.
3Measurement precision
If multiple heaters are added to the system, then the temperature control precision is improved, but the device complexity increases
Solution Approach 1:
The heating system is segmented into two functionally distinct heaters with different power ratings, positioned at different locations relative to the tank. This segmentation provides temperature zone control, allowing precise temperature management in different regions of the fluid while maintaining a relatively simple overall structure.
Solution Approach 2:
The dual-heater assembly serves multiple functions: rapid thawing, maintenance heating, and temperature regulation. By integrating these functions into a single multi-mode heater assembly, the system achieves precise temperature control without proportionally increasing device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively maintains the Aqueous Urea Solution above its freezing temperature, ensuring operational integrity of the diesel exhaust fluid tank by providing controlled and efficient heating, reducing the risk of freezing and system damage.
Implementation Method 1
it is known to use an electric resistance heater or heat exchanger using engine coolant to warm or thaw the Aqueous Urea Solution
Implementation Method 2
thermal insulation may be used to reduce heat loss and improve heat flow to the fluid in the tank
Data Source
AI summary
A heater assembly used in connection with a diesel emissions fluid tank in a vehicle, the heater assembly including a first heater connectable to an alternating current power supply; a second heater connectable to a direct current power supply within the vehicle; wherein the first heater is adapted to operate at a higher power than the second heater; wherein the first heater is closer to the tank than the second heater; a temperature sensor in sensing communication with the tank and adapted to provide a tank temperature; a control circuit connected to the second heater and the vehicle power supply, wherein the temperature sensor communicates the tank temperature to the control circuit, wherein the control circuit selectively activates the second heater to obtain a desired tank temperature.